The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
In propeller-driven submarine vehicles the propulsion propeller is arranged at the stern of the submarine vehicle in a protective housing, which protects the propeller from damage by, for example, flotsam. For a variety of submarine missions unmanned propeller-driven submarine vehicles are used which, unlike manned submarine vehicles, can achieve greater operating depths and/or operate in environments that are too dangerous for divers or the crews of manned systems. Unmanned submarine vehicles can be broadly divided into remotely operated submarine vehicles (ROV=Remotely Operated Vehicle) and autonomous submarine vehicles (AUV=Autonomous Submarine Vehicle). Remotely operated underwater vehicles (ROVs) are usually controlled by a cable. Commands are generated by a control center on a system platform, e.g. a seagoing vessel, and transmitted via the connecting cable.
Autonomous submarine vehicles (AUVs) complete their particular missions without constant supervision by human operators. Instead they follow a given mission program. Autonomous submarine vehicles can be recognized as they are assembled with a connecting cable connecting them to the system platform. Such hybrid AUVs can provide, in addition to autonomous control over a fiber optic link, data transmitted from sensors to the system platform. The connecting cable can be connected, via a plug and socket connection, to the submarine vehicle.
The connecting cable is usually connected to the stern of the submarine vehicle, so as to ensure a trouble-free connection with the continually moving submarine vehicle, and also to ensure minimum flow resistance to the submarine vehicle.
Throughout the submarine vehicle's mission, the distance between the submarine vehicle and the system platform changes, so that tensile stresses can occur in the connecting cable. In order to avoid such tensile stresses in the connecting cable causing the plug connection between the connecting cable and the submarine vehicle to become loose, i.e. the plug being pulled out of the submarine vehicle, it is usual to employ strain reliefs. With conventional strain reliefs, the connecting cable is wound several times around one or more drums attached to the structure of the submarine vehicle. Because of friction between the connecting cable and the strain relief drums the connecting cable is restrained by the strain reliefs and the end portion of the connecting cable between the strain relief and the plug connector does not have to protect the delicate connecting cable and prevent the plug from being disconnected.
The connection between the connecting cable and the arrangement of strain reliefs on the vehicle structure is complicated by a stern-mounted drive propeller, since the preferred direct locations for the cable connector on the stern are relatively inaccessible because of the position of the propeller. Further, the strain reliefs on the structure of the submarine vehicle create additional unwanted flow resistance.